Electrolytic cell.



A. H. HOOKER.

ELECTROLYTIG CELL.

APPLICATION FILED FBB.26,1912.

1,075,570. Patented oet. 14, 19313.

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A. H. HOOKER.

ELEGTROLYTIC CELL.

APPLIGATION FILED 313.26, 1912.

Patented 0013. 14, 1913.

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ALBERT H. HOOKER, 0F NIAGARA FALLS, NEW YORK, ASSIGNOR ITO IOOKER ELECTRO- CHEMICAL COMPANY, OFNEW YORK, N. Y., A CORPORATION 0F NEWT YORK.

nLEoTnoLYTIc CELL'.

Specification of Letters Patent.

` Patenteuoet. 14,1913.

Application led February 26, 1912. Serial No. 679,897.

metal chlorid solutions between approxi- -mately vertical insoluble anodesand per meable or perforated cathodes with which the diaphragm is in contact, and to .methods involved in the operation of such c ells, an' primary `object of the invention belng to provide a form of cell possessing great ampere-capacity in conjunction with relatively low starting and operating voltages.

`I have discovered that in cells of the particular type above described thereexists a heretofore unnoted relation betweenthe voltage of the cell in operation, and the vertical height of the diaphragm, the other conditions affecting the voltage, as` for example, the current density at the electrode surfaces, the distance between the electrodes,V

the material of the anodes, the resistance of the diaphragm, and the concentration of the electrolyte, being the same. Based on this discovery, I am .enabled to construct cells of large.ampere capacity, as for .example cells capable of transmitting 2000 to 6000 amperes or more, but capable nevertheless of operating at the comparatively low voltages which are feasible with electrolytic cells of relatively small dimensions and capacity.

I have found in the practical operation of electrolytic cells of the above ldefined type, and particularly when such cells are operated vatcurrent densities approximating or exceeding 100 amperes perf square foot of electrode surface, that if it l'be attempted to increase theampere-capacity of the cell by increasing proportionately the vertical and horizontal dimensions of the electrodes, the larger cell will require a distinctly higher operating voltage, the conditions as to current density, etc., remaining the same. According to thepresent invention, I. am enabled to construct cells of this type, which possess the desired larger ampere-capacity, and are nevertheless capable of operatingvat Ahigh currentdensties and at voltages notiin excess of the economical maximum.

lFora full understanding of the invention,

reference is made to the accompanying drawings wherein- Y Figure 1 graphically illustrates in the form of curves certain observed relations between the verticalv height of thediaphragm andthe starting and operatingV voltage of the cells, under conditions otherwise approximately comparable, except with respect to the temperaturev of the electrolyte. Fig. 2- is a side elevation, partly broken away, of one form of electrolytic cell embodying the invention. Y

InFig. 1, the curves marked A, BC and D indicate respectively the voltage-characteristic of electrolytic cells of the type herein defined, atthe range of current densities indicated, theA current `density being computed on the basis'of. the cathode area. The

`cathodes consisted in each case of perforated metal sheets covered by the diaphragm o n the side adjacent the anode, but the effective area of the cathode is computed as that of an imperfo'rate sheet of equal dimensions. The'descriptive character ofthe several cells reduced-,to a common areawas as follows:

A':Cat hode 32`inches lon by 36 inches high; area 1152 square inc es; ratioof heightto length=`1:0.889. i

B:-Cathode 48 inchesflong by 24 inches high; area 115.2. square inches; ratio of height to length=1 :2.

(lz-Cathode v,64 inches high; area. 1152 square inches; ratio of .height to length=1:3.555.

Dz-Cathode 96 inches long by 12 inches long by 18 inches.

high; Aarea 1152 square inches; ratio of.v

height to length=1 :8.

It will-be noted that' the cathode area is the same in all cases, and it might have been assumed that at equal current densities the starting and operating voltages would likewise be identical. Actual trial however hasv shown that this is far from being the case. For example, if a current of 1000 amperes.,

'corresponding to 125 amperes per square foot of cathode area, be passed through each cell, the starting voltages are found to be as follows: A starts at 4.96 volts, B starts at 4.40

volts, C starts at 4.07 volts, D starts at 3.70

volts. At higheror lower current densities a similar relation exists. as clearly indicated 'by the drawing, the differences in the start ing voltages becoming greater as the current densities increase. A current of 1000 amperes'oiving to cathodes of dimensions as above specified, would of course correspond to 2000 am pereslor each cell or' thestandard double-cathode type, as described for `instance in United States Patent No. or as herewith illustrated.

Referring to Fig. 2, l represents the concrete cellbody,'resting upon insulating-supports 2. by concrete blocks et, and connected to the anode bus bars 5. 6 are the recessed metal 'side plates, detachably secured by clamps 7 y which bear upon the fixed angle-iron frame uork S. 9, 9 representthe cathode ccnnecL tions to the side plates 6. 10 is one of the vertical cathode plates of i secured at its margin to the inner face of the recessed-side plates G, and covering the recessed portion thereof. 1 1 is the diaphragm of asbestos paperor the like overlying the cathode on the side adjacent the anode. "1Q is the brine inlet, and 13tlie overliow for chlorinated brine, the level' of which may be controlled by longitudinal adjustment of the glass tube14, which is of sutlicient capacity to aiiord passage also for the gaseous chlorin. Caustic liquor is Withdrawn through pipes 15, flowing through funnel 16 to thel caustic main 17. 18 is` an overflow lfor hydrocarbon liquid, when this is used, and 19 a cock for draining the cathodecompartment, both overflow and cock dischargingy into a funnel 20 leading to the main 2i.

It. will of course be-understood that the starting and other voltages shown on. Fig. .1 are not absolute, inasmuch as the voltage depends upon mafny lactors,. including the dis-y tance between the electrodes, the material of the electrodes, the temperature and. concentration of the electrolyte, etc. but other conditions being alike, the starting voltage varies directly with the height of the diaphragm, in approximately the manner indicaterh` During the operation of the c ell,

" the voltage, as a rule, exhibits a tendency to rise slowly, as the porosity ofthe diaphragm is reduced. The several curyes indicated' illustrate the eilect of a variation, in height in conjunction lwith a corresponding tem perature variation, inasmuch as a` celloperating at a relatively low voltage Will of' course tend', except. as the tempera-ture may be independently controlled, to a. relatively low temperature. The effect, of operating these several cells undery identical tempera-- ture conditions would be to lncrease somewhat the'divergence of' the several curves,

and further to accentuate the advantage of the type of' construction embodying. the hi gher ratio of the horizontal, dimension of the cathode to its vertical dimension. Based upon this heretofore unobserved relation be- -t\veen the vertical height ofthe cathode and the cell voltage, I have been able to design cells of very large amperelcapacity, which 3 are anodes of graphite, carried v erforated steel,

are capable of operating at high current densities and at economical voltages. For example, assume that it is desired to co'nstruct a cell of standard type having a capacity of 2000 amperes, to operate ata starting voltagel of 3.5 at 100 amperes per lsquare foot of cathode area.. The chart spoivs at once that this starting voltage at iis current density is characteristic of a cathode approximately 12 inches in height, under standard conditions as regards the character ol the diaphragm, distance between n electrodes, etc. `total length of the cathode must be apot" the usual double-cathode type, to two cathodes, each`12 inches high by 10 feet long. For cells of larger ampere capaci-ty itis often economical to increase somewhat the height of the cathode, in order to avoid engineering ditli'culties arising from an eX,, cessiv'e length ofthe cell body. For example, a 4000 ampere'cell maybe constructed with acathode 1:8 inches high, each cathode' bein-g 13% feet in length; the starting voltage of such a cel-lat a current density of 100 amperes per square foot will be about 3.85 volts. If, however, "conditions permit `the construction of a longer .-cell, the diahragm and cathode may be reduced in eight, such reduction affording a reduction nitud'e shown by the chart or diagram. l It :tol-lows directly from the foregoing considerations thatfit' is highly advantageous, from the point .of view of' energy etliciency, to construct the cell with. long and i relatively low' cathodes, having ofcourse due regard to the necessary strength of' the cellbodies, which are usually constructedjof reinforced concrete, and to the addition-al floor space requisite lor the long cells. The most economical type of cell will depend, therefore', upon a variety ot factors; but by the a-id ofthe foregoing considerations itis easy,

a cell having the desired characteristics. It 1s to be noted that considerations of high and' in the `ease of cells having a capacity t ofQOGGE ampres or over, that the length of a double-cathode cells, should be at least six preferably more thanthis. In case the cell has tivo ca'thodfes, as in the` standard doublecathode cell, the aggregated or total longitudinal dimension of the two cat-hotles more than this. Thisp'involves a radical departurefrom' cells as heretofore designed,

"cathodear'ea by a proportionate or approxi- It follows that 'the proxirnately4 20 feet, corresponding in azeell` lin the starting voltage ot" the orderofiiiagenergy etliciency require in all cases that the. lcathode should be relatively long andf'lovv;vl

lsingle cathode, in case of the standard" shouldbe at least thirteen times the vertical, height of a single cathode, yand preferably in Which it has'been usual to increase tfie IOO by taking account of such factors, to design and one-halftimesits verticalheight, and. 13b' mately proportionate increase of its horizontal and Vertical dimensions.V

vIt is to be understood that the principles above stated are applicable to cells having a single diaphragm and-cathode, and also to cells of the standard type having opposite cathodes with associated diaphragms,v it be-' ing essential only in the latter case that ,the combined horizontal dimension of the diaphragms, should beat least thirteen times the vertical dimension of a single diaphragm. It is. immaterial to the application of these principles Whether or not -t-he cathodes present plane surfaces. In case ofY cylindrical or similar cells, the circumferential length ofthe cathode ,is to be regarded as its horizontal dimension'.

The vabove described relation between the vertical height vof the cathode and the cellthe relation noted# becomes more-strongly accentuated as the current density is increased, and Why the low verticalheight of cathode is essential to the economical operaapproximately ,tion of cells havinga capacity of 2000 amperes or more. rlhe expression high amperage cell as used 1n the \cla1ms 1s accordingly intended to dene a\cell having a capacity of at least 2000 amperes under.

s normal Working conditions,

an insoluble anode, a permeable cathode and an interposed diaphragm in contact with said cathode, said electrodes being approximately vertically disposed, the horizontal dimension of the cathode being in excess of six and one-,halftimes its vertical-dimension, as and for the purposes set forth.

2. A high-amperage cell for the electrolysis of alkali-chlorid solutions, comprising an `insoluble anode, and a plurality of permeable cathodes with interposed diaphragms in contact therewith, said electrodes being vertically disposed, the aggregated horizontal dimensions` of the cathodes being in excess of thirteen times the vertical dimension of one of' said cathodes. v

v In testimony whereof I aiiiX my signature in presence of two witnesses.

ALBERT H. HooKER..

Witnesses H. C. SLADE, J. JFOCAZIO.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,Y

- Washington, D. C. t 

